1 /*
2 * SMP support for pSeries machines.
3 *
4 * Dave Engebretsen, Peter Bergner, and
5 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
6 *
7 * Plus various changes from other IBM teams...
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
13 */
14
15
16 #include <linux/kernel.h>
17 #include <linux/sched.h>
18 #include <linux/smp.h>
19 #include <linux/interrupt.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/spinlock.h>
23 #include <linux/cache.h>
24 #include <linux/err.h>
25 #include <linux/device.h>
26 #include <linux/cpu.h>
27
28 #include <asm/ptrace.h>
29 #include <linux/atomic.h>
30 #include <asm/irq.h>
31 #include <asm/page.h>
32 #include <asm/pgtable.h>
33 #include <asm/io.h>
34 #include <asm/prom.h>
35 #include <asm/smp.h>
36 #include <asm/paca.h>
37 #include <asm/machdep.h>
38 #include <asm/cputable.h>
39 #include <asm/firmware.h>
40 #include <asm/rtas.h>
41 #include <asm/mpic.h>
42 #include <asm/vdso_datapage.h>
43 #include <asm/cputhreads.h>
44 #include <asm/xics.h>
45 #include <asm/dbell.h>
46 #include <asm/plpar_wrappers.h>
47 #include <asm/code-patching.h>
48
49 #include "pseries.h"
50 #include "offline_states.h"
51
52
53 /*
54 * The Primary thread of each non-boot processor was started from the OF client
55 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
56 */
57 static cpumask_var_t of_spin_mask;
58
59 /*
60 * If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here
61 */
62 static void (*xics_cause_ipi)(int cpu, unsigned long data);
63
64 /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */
smp_query_cpu_stopped(unsigned int pcpu)65 int smp_query_cpu_stopped(unsigned int pcpu)
66 {
67 int cpu_status, status;
68 int qcss_tok = rtas_token("query-cpu-stopped-state");
69
70 if (qcss_tok == RTAS_UNKNOWN_SERVICE) {
71 printk_once(KERN_INFO
72 "Firmware doesn't support query-cpu-stopped-state\n");
73 return QCSS_HARDWARE_ERROR;
74 }
75
76 status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
77 if (status != 0) {
78 printk(KERN_ERR
79 "RTAS query-cpu-stopped-state failed: %i\n", status);
80 return status;
81 }
82
83 return cpu_status;
84 }
85
86 /**
87 * smp_startup_cpu() - start the given cpu
88 *
89 * At boot time, there is nothing to do for primary threads which were
90 * started from Open Firmware. For anything else, call RTAS with the
91 * appropriate start location.
92 *
93 * Returns:
94 * 0 - failure
95 * 1 - success
96 */
smp_startup_cpu(unsigned int lcpu)97 static inline int smp_startup_cpu(unsigned int lcpu)
98 {
99 int status;
100 unsigned long start_here =
101 __pa(ppc_function_entry(generic_secondary_smp_init));
102 unsigned int pcpu;
103 int start_cpu;
104
105 if (cpumask_test_cpu(lcpu, of_spin_mask))
106 /* Already started by OF and sitting in spin loop */
107 return 1;
108
109 pcpu = get_hard_smp_processor_id(lcpu);
110
111 /* Check to see if the CPU out of FW already for kexec */
112 if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){
113 cpumask_set_cpu(lcpu, of_spin_mask);
114 return 1;
115 }
116
117 /* Fixup atomic count: it exited inside IRQ handler. */
118 task_thread_info(paca[lcpu].__current)->preempt_count = 0;
119 #ifdef CONFIG_HOTPLUG_CPU
120 if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
121 goto out;
122 #endif
123 /*
124 * If the RTAS start-cpu token does not exist then presume the
125 * cpu is already spinning.
126 */
127 start_cpu = rtas_token("start-cpu");
128 if (start_cpu == RTAS_UNKNOWN_SERVICE)
129 return 1;
130
131 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
132 if (status != 0) {
133 printk(KERN_ERR "start-cpu failed: %i\n", status);
134 return 0;
135 }
136
137 #ifdef CONFIG_HOTPLUG_CPU
138 out:
139 #endif
140 return 1;
141 }
142
smp_xics_setup_cpu(int cpu)143 static void smp_xics_setup_cpu(int cpu)
144 {
145 if (cpu != boot_cpuid)
146 xics_setup_cpu();
147 if (cpu_has_feature(CPU_FTR_DBELL))
148 doorbell_setup_this_cpu();
149
150 if (firmware_has_feature(FW_FEATURE_SPLPAR))
151 vpa_init(cpu);
152
153 cpumask_clear_cpu(cpu, of_spin_mask);
154 #ifdef CONFIG_HOTPLUG_CPU
155 set_cpu_current_state(cpu, CPU_STATE_ONLINE);
156 set_default_offline_state(cpu);
157 #endif
158 }
159
smp_pSeries_kick_cpu(int nr)160 static int smp_pSeries_kick_cpu(int nr)
161 {
162 BUG_ON(nr < 0 || nr >= NR_CPUS);
163
164 if (!smp_startup_cpu(nr))
165 return -ENOENT;
166
167 /*
168 * The processor is currently spinning, waiting for the
169 * cpu_start field to become non-zero After we set cpu_start,
170 * the processor will continue on to secondary_start
171 */
172 paca[nr].cpu_start = 1;
173 #ifdef CONFIG_HOTPLUG_CPU
174 set_preferred_offline_state(nr, CPU_STATE_ONLINE);
175
176 if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
177 long rc;
178 unsigned long hcpuid;
179
180 hcpuid = get_hard_smp_processor_id(nr);
181 rc = plpar_hcall_norets(H_PROD, hcpuid);
182 if (rc != H_SUCCESS)
183 printk(KERN_ERR "Error: Prod to wake up processor %d "
184 "Ret= %ld\n", nr, rc);
185 }
186 #endif
187
188 return 0;
189 }
190
191 /* Only used on systems that support multiple IPI mechanisms */
pSeries_cause_ipi_mux(int cpu,unsigned long data)192 static void pSeries_cause_ipi_mux(int cpu, unsigned long data)
193 {
194 if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id())))
195 doorbell_cause_ipi(cpu, data);
196 else
197 xics_cause_ipi(cpu, data);
198 }
199
pSeries_smp_probe(void)200 static __init void pSeries_smp_probe(void)
201 {
202 xics_smp_probe();
203
204 if (cpu_has_feature(CPU_FTR_DBELL)) {
205 xics_cause_ipi = smp_ops->cause_ipi;
206 smp_ops->cause_ipi = pSeries_cause_ipi_mux;
207 }
208 }
209
210 static struct smp_ops_t pSeries_mpic_smp_ops = {
211 .message_pass = smp_mpic_message_pass,
212 .probe = smp_mpic_probe,
213 .kick_cpu = smp_pSeries_kick_cpu,
214 .setup_cpu = smp_mpic_setup_cpu,
215 };
216
217 static struct smp_ops_t pSeries_xics_smp_ops = {
218 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */
219 .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */
220 .probe = pSeries_smp_probe,
221 .kick_cpu = smp_pSeries_kick_cpu,
222 .setup_cpu = smp_xics_setup_cpu,
223 .cpu_bootable = smp_generic_cpu_bootable,
224 };
225
226 /* This is called very early */
smp_init_pseries(void)227 static void __init smp_init_pseries(void)
228 {
229 int i;
230
231 pr_debug(" -> smp_init_pSeries()\n");
232
233 alloc_bootmem_cpumask_var(&of_spin_mask);
234
235 /*
236 * Mark threads which are still spinning in hold loops
237 *
238 * We know prom_init will not have started them if RTAS supports
239 * query-cpu-stopped-state.
240 */
241 if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) {
242 if (cpu_has_feature(CPU_FTR_SMT)) {
243 for_each_present_cpu(i) {
244 if (cpu_thread_in_core(i) == 0)
245 cpumask_set_cpu(i, of_spin_mask);
246 }
247 } else
248 cpumask_copy(of_spin_mask, cpu_present_mask);
249
250 cpumask_clear_cpu(boot_cpuid, of_spin_mask);
251 }
252
253 /* Non-lpar has additional take/give timebase */
254 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
255 smp_ops->give_timebase = rtas_give_timebase;
256 smp_ops->take_timebase = rtas_take_timebase;
257 }
258
259 pr_debug(" <- smp_init_pSeries()\n");
260 }
261
smp_init_pseries_mpic(void)262 void __init smp_init_pseries_mpic(void)
263 {
264 smp_ops = &pSeries_mpic_smp_ops;
265
266 smp_init_pseries();
267 }
268
smp_init_pseries_xics(void)269 void __init smp_init_pseries_xics(void)
270 {
271 smp_ops = &pSeries_xics_smp_ops;
272
273 smp_init_pseries();
274 }
275